Commercial barium-impregnated polyethylene spheres (BIPS) were administered to 12 healthy adult cats according to the manufacturer's instructions (30 small BIPS and 10 large BIPS to each cat) together with 60 g of a canned food. Radiographs were taken at hourly intervals until seven hours after feeding, and then at eight, 10, 12, 14, 17, 23 and 30 hours or until all the BIPS had left the stomach and at least 50 per cent had entered the colon. Six cats were sedated immediately after being fed the BIPS and six cats remained unsedated. For small BIPS (1.5 mm diameter), the gastric transit time (first exit of BIPS from the stomach) in the sedated cats had a median of 6 hours (range 3 to 8) and in the unsedated cats a median of 2.5 hours (range 2 to 6). Values for other transit times were not significantly different between the two groups, and the pooled data revealed a median 50 per cent gastric emptying time of 6.4 hours (range 2.5 to 10.9), a complete gastric emptying time of 12 hours (range 6 to 27), an orocaecal transit time (first appearance of BIPS in the colon) of 6.5 hours (range 4.0 to 12.0) and a 50 per cent orocaecal transit time of 8.8 hours (range 4.6 to 12.8). The gastrointestinal transit of large BIPS (5 mm diameter) was significantly correlated with the passage of small BIPS but, except for the complete gastric emptying time, was significantly slower.